The invention relates to devices for determining type and dampness of textiles, appliances utilizing such devices, methods for detecting type and dampness of textiles, and methods for determining a filling level of a container. The device includes at least one sending element and one receiving element for sending and receiving electromagnetic radiation and also an evaluation circuit connected to the receiving element. The radiation sent by the sending element and reflected and/or transmitted by the textile can be received by the receiving element and evaluated in the evaluation circuit.
German Published, Non-Prosecuted Patent Application DE 37 06 056 A1 discloses a method of generating and detecting optical spectra and also a switching and sensor system that are intended for sewing and textile automation. In the case of the prior-art method, a radiation device that includes at least two, preferably three, semiconductor emitters is used. These send an optical radiation of differing wavelength, which ranges from the ultraviolet range through the visible range into the infrared range, the radiation being modulated at a specific frequency. The radiation is directed onto a common surface or a single measuring point of a medium. Subsequently, the radiation reflected or allowed through by the medium is sensed by a correspondingly adapted receiver and fed to a downstream electronic evaluation device. With the known method, it is intended to detect differences in a material or medium in the radiation spectral range from ultraviolet to infrared using automatic machines or robots in the sewing and making-up of clothing, the textile industry and general production engineering. However, the document does not indicate how a switching and sensor system of this type with a sending element and a receiving element can be used.
It is accordingly an object of the invention to provide a device for determining type and dampness of textiles, appliances applying the device, a method for detecting type and dampness of textiles, and a method for determining a filling level of a container that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and treats textiles appropriately even when directions on how a textile is to be treated cannot be obtained.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a device typically used in appliances such as washing machines, laundry dryers, spin dryers, machines for dry cleaning, and machines for dying textiles. The appliances include a drum. The device detects properties of textiles and includes a sending element, a receiving element, and an evaluation circuit. The sending element sends electromagnetic radiation to a textile. The receiving element receives electromagnetic radiation that is transmitted through and/or reflected from the textile. The evaluation circuit connects to the receiving element and evaluates the electromagnetic radiation received by the receiving element.
With the objects of the invention in view, there is also provided a method of detecting properties of textiles in an appliance. The first step of the method is providing a container. The next step is irradiating a textile with electromagnetic radiation from a transmitting element. The next step is receiving electromagnetic radiation from the textile with a receiving element. The next step is evaluating the electromagnetic radiation received by the receiving element with an evaluation unit.
In other words, the method provides that at least one sending element irradiates the textile with electromagnetic radiation. Then, at least one receiving element receives radiation reflected and/or transmitted by the textile. Next, an evaluation circuit evaluates this radiation.
According to the invention, electromagnetic radiation, i.e. radiation in the UV, visible or IR range, is used to determine properties of a textile. In the treating appliance, the textile is treated in some way, for example wetted with a liquid medium, dried, spun, starched, ironed, mangled, portioned, cut, dry-cleaned, and/or are changed in some other way. The treating appliance is correspondingly a laundry treating appliance: e.g. a washing machine, a laundry dryer, a spin dryer, a smoothing iron, a laundry mangle, a machine for dry cleaning, or for dying textiles. When the term xe2x80x9cgarmentxe2x80x9d is used hereafter, it is always to be understood as meaning any type of textile medium.
For the purposes of the invention, a sending element is any emitter which emits electromagnetic radiation, that is for example an incandescent lamp, a halogen lamp, a mercury-vapor lamp, a light-emitting diode, a laser diode, a gas laser, and the like. Particularly suitable are emitters that emit a narrowband spectrum, or emitters that generate monochromatic light. Suitable are monochromatic or narrowband emitters in conjunction with one or more receivers. The receivers may receive across a broadband as long as they cover the bandwidth of the radiation emitted by the emitter or emitters. Alternatively, broadband emitters and assigned wavelength-selective receivers can be used. Instead of wavelength-selective receivers, broadband emitters and/or receivers can also be used, if either the emitters or the receivers are assigned narrowband filters. Preferably, a plurality of sending elements is also used. A plurality of sending elements generates either different spectra or monochromatic light of different wavelengths. In a corresponding way, the receiving elements are adapted to the sending elements. These receiving elements sense either a certain band within the sending radiation emitted by the sending element or the sending elements. Alternatively, they can sense precisely the wavelength that the sending element or the sending elements are emitting, if the sending elements are monochromatic light sources. Consequently, suitable receiving elements include photodiodes or phototransistors. If the sending element emits radiation in a number of wavelength ranges, a plurality of receiving elements are preferably used, in particular photodiodes, with an upstream filter or grating, or a photodiode array or CCDs (=charged coupled devices), which absorb light and generate corresponding electrical signals. The electrical signals are preferably amplified and fed to the evaluation circuit. The received light must be selected according to wavelengths. This optionally takes place by a filter, a prism, or a diffraction grating.
The light emitted by the sending element or the sending elements is partly absorbed, but partly reflected or transmitted, by the textiles, in particular the garment. In this case, the reflected light is primarily suitable for the detection, because the transmitted light makes up only a small fraction of the sending radiation and the proportion of the transmitted radiation greatly decreases with increasing thickness of the textiles.
Based on the spectra or wavelengths reflected by the textiles from a spectrum sent, the properties of the textiles can be concluded. This similarly applies to the transmission spectra. In this case, the spectra are either evaluated over a specific spectral range or only in respect of specific frequencies or wave numbers. For the purposes of the invention, properties of the textiles are to be understood as meaning both permanent properties of the textiles, i.e. their chemical composition of various fibers, for example cotton, wool, silk, synthetic fibers, or their type of fabric, and temporary properties, which result from the treatment with specific media. Particularly relevant here is the wetting by water or an organic solvent, by detergent solution or the treatment by starch or some other finishing agent.
The evaluation circuit obtains from the received signals a signal that either is directly of significance for the operator or is relevant for the further treatment of textiles. For example, a signal to warn the operator against incorrectly programming the treating appliance can be obtained. When the evaluation circuit is used in a washing machine, the evaluation circuit obtains from the electromagnetic radiation received, for example in the IR range, information on the type of textile, for example silk, and produces an optical or acoustic signal if the operator sets a temperature at which silk would be damaged. In another case, the heating-up of the washing machine to a temperature above the temperature permissible for silk is automatically prevented and a program which makes allowance for the properties of the textiles loaded into the laundry drum is carried out by the evaluation circuit, so that none of the textiles are damaged, discolored, etc.
According to a special embodiment of the invention, the sensing of temporary properties of textiles, for example the dampness, is considered when providing a treatment in the washing machine or the laundry dryer that is adapted to the desired residual dampness. Consequently, if the operator has set a certain residual dampness, a respective dampness state is sensed continuously or at specific time intervals during the spinning or drying process based on the electromagnetic radiation reflected and/or transmitted by the textiles and a remaining running time of the spin dryer or of the drying program is calculated from this. When the residual dampness is achieved, the spinning or drying is discontinued.
According to the invention, the filling level or loading of a laundry-treating machine can also be sensed. This already takes place for example when machine is being loaded, if each garment is sensed by the sensor, preferably by a plurality of sensors, so that information on the surface area consumed by the textiles within the laundry drum can be determined. In the volumetric determination of the drum filling level, the reflections induced by the rear wall of the drum are considered. The evaluation circuit or an already existing control circuit then calculates from this the amount of water required for cleaning the textiles, the amount of detergent, the type of mechanical treatment and the maximum permissible temperature, taking into account the type or types of textile. Finally, the evaluation circuit decides on the duration of the laundry treatment, that is for example the washing, spinning, drying, and cleaning.
In addition, information obtained from the textiles can be combined with other information already existing in the laundry-treating machine: for example, considering the turbidity of the detergent solution, in order to determine the duration and/or the temperature of the washing process. According to one embodiment of the laundry-treating appliance, the evaluation circuit is connected to the program selection control in such a way that a specific program is selected by the laundry-treating appliance based on the detected garments in accordance with the material or the dampness of the garments. This means that, if for example a garment of silk is detected among the garments, the maximum temperature of the program is selected by the program selection control in such a way that the garment of silk does not shrink or become damaged by too high a temperature.
One advantage of the appliance is also that the device for detecting properties of a textile can also be used when the textile is not to undergo treatment but it is just intended to detect the material composition of the textile. This might be necessary when the label showing the material composition is no longer present in the textile or has been removed. The user then learns from the device in conjunction with a display unit the materials of which the textile is constructed, and can then decide which further treatment it is to be given.
Particularly for the case of an individual textile measurement of this type, but also for other detection purposes, it is suitable if the location irradiated with infrared radiation is made perceptible for the user by simultaneous emission of visible radiation. For this purpose, for example, a visible illumination annularly surrounding the location of the textile irradiated by the IR radiation is generated on the textile. Similarly, the location irradiated by infrared radiation can be made identifiable by a red dot generated by an LED.
Sending and receiving elements can be used in various positions inside or outside the treating appliance. In a laundry dryer, the receiving element or the receiving elements are advantageously disposed in the top region of the loading opening. Similarly, a sending element is disposed there. A lamp provided for illuminating the interior of the laundry drum also may be suitable as a sending element. Alternatively, sending and/or receiving elements can be used in the region above the loading opening of the rear bottom wall of the laundry drum, in particular whenever a lamp is already provided there for interior illumination of the drum. If this lamp is a halogen lamp or some other broadband emitter, it is already suitable as a sending element. In order however to eliminate undesired extraneous light effects, penetrating for example through the porthole of the rear bottom wall of the laundry drum, the light emitted by the sending element is modulated in a specific way and the reflected or emitted light is only used when it has the same modulation.
Sending and receiving elements are preferably used in conjunction with optical devices, in particular focusing lenses, optical waveguides, and also optical and/or electrical configurations for amplifying optical or electrical signals.
Filters are also advantageously used to separate narrow spectral ranges. Suitable examples of filters are diffraction gratings, which are transmissive at different angles for different wavelengths, prisms, holographic filters, gratings, and the like. Particularly suitable are also graduated filters, from which irradiated broadband light is coupled at different locations. A preferably alternative is optical waveguides. Optical wavelguides allow sending and transmitting elements to be disposed at a place inside the treating appliance that is exposed only to low mechanical loads and which couple the electromagnetic radiation into the region in which the textiles are being treated via an optical waveguide and/or pass it from this region via an optical waveguide to the receiving element.
The use of the optical waveguides has the further advantage that high temperatures, which are often used in the treatment of textiles, for example within the laundry drum of a washing machine or the dryer drum of a laundry dryer, do not influence the optical elements, such as for example the sending and receiving elements and also the optics assigned to them, so that no measures to balance or compensate temperature fluctuations at the sending and/or receiving elements are necessary. Another advantage is that low-cost sending and/or receiving elements can be used. Low-cost sending and/or receiving elements have lower requirements in terms of temperature stability and, therefore, have to be less stable with respect to the influences that are present within the drum of a laundry dryer or a washing machine and can adversely influence sending and receiving elements. The same advantage also applies to the use of control or evaluation electronics assigned to the respective sending and receiving elements.
However, the invention does not exclude the possibility of the evaluation circuits, including the sending and receiving elements, being disposed directly in the treatment region of the textiles.
Sending and receiving elements are preferably protected against soiling occurring within the treatment space of the textiles in the form of fluff and dust, in that an air stream is directed past the sending or receiving elements. Inside a laundry dryer, the circulating air of the dryer or an air stream fed in from the outside, which for example flushes the circulating air of the dryer around in a countercurrent process, are suitable for this. In this case, ambient air or dryer air cleaned by a filter is blown firstly passed the sending and receiving elements and then into the dryer drum. However, the sending and receiving elements can also be cleaned by garments being moved past them during the cleaning operation. In the case of a washing machine, guidance of the water jet filling the laundry tub can be provided in such a way that it rinses away a covering shielding the IR radiation source.
A protective glass shields the sending and/or receiving element from the treatment space. Preferably, the protective glass shields can be removed by the user for cleaning.
Preferably, an automatic adjustment between a sent signal and a received signal in the absence of textiles to be treated also takes place. The automatic adjustment subtracts errors caused by contaminants within the treatment space, i.e. in particular on a glass shielding sending and receiving elements: for example, in the subsequent measurement performed on textiles as differential signals from the signals then measured. The sending and/or receiving elements can, for example, be respectively calibrated when the appliance is switched on.
Wavelengths in the near and middle infrared ranges (NIR and MIR ranges) are particularly suitable for textile detection. Within this wavelength range, organic fabrics, i.e. textiles, undergo molecular vibrations when exposed to external energy. Depending on the type of textile, and in accordance with its chemical composition, it absorbs corresponding spectral components from an electromagnetic radiation with which it is irradiated, or reflects them, and/or transmits them. The energy is preferably coupled into the textiles with a broadband emitter, for example an incandescent lamp, a halogen lamp, or a light-emitting diode, but other, narrowband emitters are also suitable. The textiles and the water contained therein absorb energy from the electromagnetic radiation over the entire irradiated spectral range of the light source. The light not absorbed is reflected and/or transmitted, part of this light is passed to the evaluation circuit by the receiving element or elements. If the received radiation represents a spectrum, a spectral breakdown of the spectrum received is preferably conducted there. Particularly suitable is the Fourier transformation of the spectra (FTIR). This breakdown can be performed according to the following principles. The electromagnetic signals are irradiated by a filter or by a plurality of filters onto the receiving elements. The receiving elements can be formed by individual receiving diodes, individual phototransistors, or by receiving elements configured in the form of a CCD array. Instead of the filters disposed ahead of the receiving elements, diffraction gratings can also be provided.
A coupling-in optical system, which apart from a grating or a filter, also includes a lens system. Preferably, the lens system is a converging lens.
The selection of which spectral ranges are actually used or blocked by the receiving elements depends on the object to be detected. If it is accordingly known which types of textiles come into consideration at all for the treating appliance, it is possible to provide correspondingly narrowband receiving elements, which specifically absorb wavelength ranges relevant in respect of these textiles, in order in this way to allow an analysis of the chemical composition or the instantaneous state of the textile. In this case, it is also possible to determine specific types of soiling of a textile: for example, proteinaceous or greasy soiling. The same also applies correspondingly to the evaluation circuit. It is similarly possible to extend the spectroscopic investigation of the textiles into the visible range, in order also to be able to determine the color of the textiles.
Because the moisture content of a textile also has an influence on its absorption and/or transmission spectrum in a specific wavelength range. Preferably, those wavelength ranges in which either a dependency of this type does not exist or it at least has no perceptible influence on the distinguishability between various types of textiles are preferably selected for the measurement of the dampness on the one hand and the type of textile on the other hand.
Alternatively, information which takes into account the dependence of the spectrum of a textile on the moisture taken up is also stored in a memory unit assigned to the evaluation circuit, in order to correct spectral measurements in a way corresponding to the desired data, whether concerning the type of the textile or concerning the moisture content.
Various properties of the spectra are suitable in the evaluation of the spectra, for example their slope, the height of peaks, the relative height of various peaks, derivative functions from the spectra, and variables obtained from the spectra. A factor analysis of the spectra is preferably also conducted. All the data thereby obtained can be stored in a memory unit and are then available for comparison with later measurement results.
In a particularly preferred embodiment of the invention, the evaluation unit includes a fuzzy logic or a neural network, in which various properties for the detection of permanent properties of textiles can be detected. Examples of the properties to be detected include chemical composition, temporary properties of textiles such as moisture content, temperature, or wetting by a liquid. Spectra for various types of textiles, in particular for various degrees of dampness of these textiles, are preferably available in the memory unit or are successively stored during the operation of the treating appliance and are respectively taken into account during the treatment or processing of textiles.
The drum filling level of a washing machine or a laundry dryer can also be determined by the device for detecting the properties of textiles, in that the intensity of the reflected light is ascertained. This utilizes the fact that textiles scatter the light less than the laundry drum, which is built from high-grade steel. In principle, the difference between the materials of the laundry drum and garments can be utilized to sense the volume filled with laundry within the laundry-treating appliance. This is preferably involves performing an integral measurement of the spectra.
The device is likewise suitable for detecting when the drum is at a standstill because the measured spectra do not change over time in this case. Tearing of the drive belt may cause such a standstill of the drum.
In the case of smoke being produced within the laundry drum, the spectrometer can also be used in conjunction with the evaluation circuit as a smoke detector. When a certain density of smoke is reached, the spectra of the garments can no longer be detected. The evaluation circuit then generates a signal triggering a fire alarm at a receiver, for example at a fire station, if the domestic appliance is connected to a data network. Alternatively, an acoustic fire alarm is connected to the laundry-treating appliance or is provided in the home.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a device for determining type and dampness of textiles, appliances applying the device, a method for detecting type and dampness of textiles, and a method for determining a filling level of a container, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.